Google Spreadsheet JSON ExportHow-to at http://blog.pamelafox.org/2013/06/exporting-google-spreadsheet-as-json.html

exportjson.js

// Includes functions for exporting active sheet or all sheets as JSON object (also Python object syntax compatible).
// Tweak the makePrettyJSON_ function to customize what kind of JSON to export.


// ignore row/column if first row/column contains this key
var IGNORE_KEYS = ["ignore", "void"];
var EXPORT_FOLDER = "JsonExport";
var EXPORT_TYPE_JSON = "Json";
var EXPORT_TYPE_CSV = "Csv";

var FUNCTION_EXPORT_JSON = "exportJson";
var FUNCTION_EXPORT_CSV = "exportCsv";

function onOpen() {
  var ui = SpreadsheetApp.getUi();
  ui.createMenu('Export')
      .addItem('Preview Json', 'previewJson')
      .addItem('Export Json', FUNCTION_EXPORT_JSON)
      .addItem('Export Csv', FUNCTION_EXPORT_CSV)
      .addItem('Options...', 'optionsDialog')
      .addToUi();
}
    
function optionsDialog() {
  var htmlOutput = HtmlService
    .createTemplateFromFile('options')
    .evaluate()
    .setWidth(250)
    .setHeight(150);
  SpreadsheetApp.getUi().showModalDialog(htmlOutput, 'Options');
}

function saveOptions(options) {
  var ui = SpreadsheetApp.getUi();
  //ui.alert(JSON.stringify(options));
  
  if (!options.hasOwnProperty('exportKeyed'))
    options.exportKeyed = false;
  
  if (!options.hasOwnProperty('stopOnBlank'))
    options.stopOnBlank = false;
  
  if (!options.hasOwnProperty('encrypt'))
    options.encrypt = false;
  
  var properties = PropertiesService.getUserProperties();
  properties.setProperty('options', JSON.stringify(options));
}

function getOptions() {
  var properties =  PropertiesService.getUserProperties();
  var options = JSON.parse(properties.getProperty('options'));
  if (options == null)
    options = {};
  
  if (!options.hasOwnProperty('exportKeyed'))
    options.exportKeyed = false;
  if (!options.hasOwnProperty('stopOnBlank'))
    options.stopOnBlank = true;
  if (!options.hasOwnProperty('encrypt'))
    options.encrypt = true;
  
  return options;
}

function previewJson(e) {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheet = ss.getActiveSheet();
  var options = getOptions();
  options.exportType = EXPORT_TYPE_JSON;
  var rowsData = getRowsData_(sheet, options);
  var json = JSON.stringify(rowsData, parseArray, 4);
  return showPreview(json);
}

function showPreview(text) {
  var ui = SpreadsheetApp.getUi();
  ui.alert(text);
}

function exportJson(e) {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheet = ss.getActiveSheet();
  var options = getOptions();
  options.exportType = EXPORT_TYPE_JSON;
  var rowsData = getRowsData_(sheet, options);
  var json = JSON.stringify(rowsData, parseArray);
  
  var fileName = sheet.getName();
  
  // if set to encrypt
  if (options.encrypt) {
    json = EncryptDecrypt(json);
    fileName += ".bytes";
  }
  else
    fileName += ".json";
  
  exportData(json, ss, fileName);
}

function exportCsv(e) {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheet = ss.getActiveSheet();
  var options = getOptions();
  options.exportType = EXPORT_TYPE_CSV;
  var rowsData = getRowsData_(sheet, options);
  
  // start convert to csv
  var csv = "";

  // loop through the data in the range and build a string with the csv data
  if (rowsData.length > 1) {
    for (var row = 0; row < rowsData.length; row++) {
      for (var col = 0; col < rowsData[row].length; col++) {
        // if has a quote use double quotes instead
        rowsData[row][col] = rowsData[row][col].toString().replace(/\"/g, "\"\"");
        
        // if cell data has comma, newline, or quotes need to surround it with quotes
        if (rowsData[row][col].toString().indexOf(",") != -1 || rowsData[row][col].toString().indexOf("\n") != -1 || rowsData[row][col].toString().indexOf("\"\"") != -1) {
          rowsData[row][col] = "\"" + rowsData[row][col] + "\"";
        }
      }
      // join each row's columns
      if (row < rowsData.length-1) {
        csv += rowsData[row].join(",") + "\r\n";
      }
      // last row has no carriage return
      else {
        csv += rowsData[row];
      }
    }
  }
  
  var fileName = sheet.getName();
  
  // if set to encrypt
  if (options.encrypt) {
    csv = EncryptDecrypt(csv);
    fileName += ".bytes";
  }
  else
    fileName += ".csv";
  
  exportData(csv, ss, fileName);
}

function exportData(data, ss, fileName) {
  // get folder to export to
  var currentFolder = DriveApp.getFileById(ss.getId()).getParents();
  if (currentFolder.hasNext())
    currentFolder = currentFolder.next();
  else
    currentFolder = DriveApp.getRootFolder();
  
  var exportFolder = currentFolder.getFoldersByName(EXPORT_FOLDER);
  if (exportFolder.hasNext())
    exportFolder = exportFolder.next();
  else
    exportFolder = currentFolder.createFolder(EXPORT_FOLDER);
  
  // delete existing file
  /* Hash file name
  var fileName = Utilities.base64Encode(Utilities.computeDigest(Utilities.DigestAlgorithm.SHA_256, sheet.getName())) + ".bytes";
  Logger.log(Utilities.computeDigest(Utilities.DigestAlgorithm.SHA_256, sheet.getName()).reduce(function(str,chr) {
    chr = (chr < 0 ? chr + 256 : chr).toString(16);
    return str + (chr.length==1?'0':'') + chr;
  },''));
  */
  
  var existingFiles = exportFolder.getFilesByName(fileName);
  while (existingFiles.hasNext()) {
    existingFiles.next().setTrashed(true);
  }
  var file = exportFolder.createFile(fileName, data);
  showURL(file.getUrl());
}

function parseArray(key, value) {
  if (value && typeof key == "string" && key.indexOf('[]') > -1) {
    var splitStr = value.split(',');
    var isNumber = true;
    var splitNum = [];
    for (var i=0; i<splitStr.length; i++) {
      isNumber = isNumber && !isNaN(splitStr[i]);
      if (isNumber)
        splitNum.push(+splitStr[i]);
      else
        break;
    }
    if (isNumber)
      return splitNum;
    else
      return splitStr;
  }
  else
    return value;
}

function EncryptDecrypt(value) {
  var key = SpreadsheetApp.getActiveSpreadsheet().getRange("Warning!D31").getValue();
  var keyLength = key.length;
  var str = [];
  
  for (var i=0; i<value.length; i++) {
    str[i] = String.fromCharCode(value.charCodeAt(i) ^ key.charCodeAt(i%keyLength))
  }
  
  return str.join('');
}

function showURL(href){
  var htmlOutput = HtmlService
    .createHtmlOutput('<a href="'+href+'" target="_top" download>Download</a>')
    .setWidth(200)
    .setHeight(50);
  SpreadsheetApp.getUi().showModalDialog(htmlOutput, 'File Generated');
}

// getRowsData iterates row by row in the input range and returns an array of objects.
// Each object contains all the data for a given row, indexed by its normalized column name.
// Returns an Array of objects.
function getRowsData_(sheet, options) {
  // Get frozen rows or just the top row
  var headerRows = Math.max(1, sheet.getFrozenRows());
  var headersRange = sheet.getRange(1, 1, headerRows, sheet.getMaxColumns());
  var headers = headersRange.getValues()[0];
  var dataRange = sheet.getRange(headerRows+1, 1, sheet.getMaxRows(), sheet.getMaxColumns());
  var objects = getObjects_(dataRange.getValues(), headers, options);
  return objects;
}

// For every row of data in data, generates an object that contains the data. Names of
// object fields are defined in keys.
// Arguments:
//   - data: JavaScript 2d array
//   - keys: Array of Strings that define the property names for the objects to create
function getObjects_(data, keys, options) {
  var objectDicts = [];
  var objectLists = [];
  var keyedObjects = {};
  for (var i = 0; i < data.length; ++i) {
    var objectDict = {};
    var objectList = [];
    // skip or stop when encounter blank row key
    if (isCellEmpty_(data[i][0])) {
      if (options.stopOnBlank)
        break;
      else
        continue;
    }
    // check to ignore row
    if (IGNORE_KEYS.indexOf(data[i][0]) > -1) {
      continue;
    }
    var hasData = false;
    for (var j = 0; j < data[i].length; ++j) {
      // stop when encounter blank column key
      if (isCellEmpty_(keys[j])) {
        if (options.stopOnBlank)
          break;
        else
          continue;
      }
      // check to ignore column
      if (IGNORE_KEYS.indexOf(keys[j]) > -1) {
        continue;
      }
      var cellData = data[i][j];
      objectDict[keys[j]] = cellData;
      objectList.push(cellData);
      hasData = true;
    }
    if (hasData) {
      objectDicts.push(objectDict);
      keyedObjects[data[i][0]] = objectDict;
      objectLists.push(objectList);
    }
  }
  
  if (options.exportType == EXPORT_TYPE_JSON) {
    if (options.exportKeyed)
      return keyedObjects;
    else
      return objectDicts;
  }
  else if (options.exportType == EXPORT_TYPE_CSV) {
    // need to add the keyrow to first row of csv
    var allKeys = [];
    for (var i=0; i < keys.length; i++) {
      if (IGNORE_KEYS.indexOf(keys[i]) > -1) {
        continue;
      }
      
      if (isCellEmpty_(keys[i])) {
        if (options.stopOnBlank)
          break;
        else
          continue;
      }
      
      allKeys.push(keys[i]);
    }
    
    objectLists.splice(0, 0, allKeys);
    return objectLists;
  }
}

// Returns true if the cell where cellData was read from is empty.
// Arguments:
//   - cellData: string
function isCellEmpty_(cellData) {
  return typeof(cellData) == 'string' && cellData == "";
}

options.html

<!DOCTYPE html>
<html>
  <head>
    <base target="_top">
  </head>
  <body>
    <? var options = getOptions(); ?>
    <form onsubmit="event.preventDefault(); google.script.run.saveOptions(this)">
    <input name="exportKeyed" type="checkbox" value="true" <? if (options.exportKeyed) { ?>checked<? } ?>/> Export Keyed<br /> 
    <input name="stopOnBlank" type="checkbox" value="true" <? if (options.stopOnBlank) { ?>checked<? } ?>/> Stop on Blank<br /> 
    <input name="encrypt" type="checkbox" value="true" <? if (options.encrypt) { ?>checked<? } ?>/> Encrypt Output<br /> <br/>
    <button type="submit" value="Submit">Save</button>
    </form>
  </body>
</html>